1. Field of the Invention
The present invention relates to a camera system that includes an imaging apparatus and an illumination apparatus.
2. Description of the Related Art
Conventionally, in an imaging apparatus capable of recording moving images, such as a video camera, when an object is dark, imaging can be performed with a video light turned on to act as auxiliary light. For example, Japanese Patent Application Laid-Open No. 11-271850 discusses a video camera system in which a video light is attached to a video camera, wherein the video camera outputs light control information and the video light performs light control based on the light control information. Further, Japanese Patent Application Laid-Open No. 11-271850 discusses suitably setting the exposure during imaging by calculating the exposure of the object to be imaged by the video camera and controlling the amount of light emitted from the video light based on the calculation result.
However, in the technique discussed in Japanese Patent Application Laid-Open No. 11-271850, if imaging is performed using an auto-exposure (AE) lock function, in which the exposure control value used for exposure control is fixed, it may be impossible to perform imaging as intended by the photographer.
Consider, for example, a case in which an AE lock button is pressed in a state in which an object A is in the center of an image plane as illustrated in FIG. 7A. When the AE lock button is pressed, the weighting given to the object luminance near the center of the image plane is increased so that the exposure for the object in the center of the image plane is appropriate. Consequently, since the weighting given to the luminance of the relatively bright object A in FIG. 7A is increased, it is determined that the video light does not need to be turned on. Further, an exposure control value is calculated so that the exposure of the object in the center of the image plane is appropriate, and while the AE is locked the exposure is fixed at the calculated exposure control value.
Subsequently, if the framing is changed so that a background that is darker than the object A is in the center of the image plane, the weighting given to the dark background is increased. Therefore, it is determined that the video light needs to be turned on, and thus the video light is turned on. However, at this stage the exposure control value is fixed by the AE lock, and thus is the same as that illustrated in FIG. 7A. Consequently, by changing the video light from off to on as illustrated in FIG. 7B without changing the exposure control value, the whole of the image plane becomes brighter, which causes the object A, which had an appropriate exposure when the AE was locked, to become overexposed.
Similarly for the opposite case, when the AE was locked, if the video light is on, and it is determined that the video light does not need to be on due to a change in the framing, the object A, which had an appropriate exposure when the AE was locked, becomes underexposed.
Thus, if the video light is controlled to be turned on and off based on the luminance of an object, when imaging is performed using an AE lock function, it may be impossible to perform imaging as intended by the photographer.